Centre Number Candidate Number For Examiner s Use Surname Other Names Candidate Signature Examiner s Initials General Certificate of Education Advanced Subsidiary Examination June 2015 Question 1 2 Mark Physics A PHYA1 3 4 Unit 1 Particles, Quantum Phenomena and Electricity 5 Tuesday 19 May 2015 9.00 am to 10.15 am 6 7 For this paper you must have: a pencil and a ruler a calculator a Data and Formulae Booklet (enclosed). TOTAL Time allowed 1 hour 15 minutes Instructions Use black ink or black ball-point pen. Fill in the es at the top of this page. Answer all questions. You must answer the questions in the spaces provided. around each page or on blank pages. Do all rough work in this book. Cross through any work you do not want to be marked. Show all your working. Information The marks for questions are shown in brackets. The maximum mark for this paper is 70. You are expected to use a calculator, where appropriate. A Data and Formulae Booklet is provided as a loose insert. You will be marked on your ability to: use good English organise information clearly use specialist vocabulary where appropriate. (JUN15PHYA101) /E4 PHYA1
2 Answer all questions in the spaces provided. 1 Table 1 contains five statements that refer to isotopes and some radium isotopes. Table 1 223 88 Ra 224 88 Ra 225 88 Ra 226 88 Ra Isotope with the smallest mass number Isotope with most neutrons in nucleus Isotope with nucleus which has the largest specific charge Isotope decays by β decay to form 225 89 Ac Isotope decays by alpha decay to form 220 86 Rn 1 (a) Complete Table 1 by ticking one in each row to identify the appropriate isotope. The first row has been completed for you. [4 marks] 1 (b) (i) An atom of one of the radium isotopes in Table 1 is ionised so that it has a charge of +3.2 10 19 C. State what happens in the process of ionising this radium atom. [1 mark] 1 (b) (ii) The specific charge of the ion formed is 8.57 10 5 Ckg 1. Deduce which isotope in the table has been ionised. Assume that both the mass of a proton and the mass of a neutron in the nucleus is 1.66 10 27 kg. isotope =... 8 (02)
3 2 The equation shows an interaction between a proton and a negative kaon that results in the formation of particle, X. K + p K + + K 0 + X 2 (a) (i) State and explain whether X is a charged particle. 2 (a) (ii) State and explain whether X is a lepton, baryon or meson. 2 (a) (iii) State the quark structure of the K, K + and the K 0. K... K +... K 0... 2 (a) (iv) Strangeness is conserved in the interaction. Determine, explaining your answer, the quark structure of X. 10 Turn over (03)
4 3 (a) Baryons, mesons and leptons are affected by particle interactions. Write an account of these interactions. Your account should: include the names of the interactions identify the groups of particles that are affected by the interaction identify the exchange particles involved in the interaction give examples of two of the interactions you mention. The quality of your written communication will be assessed in your answer. [6 marks] (04)
5 3 (b) Draw a labelled Feynman diagram that represents a particle interaction. Turn over for the next question 9 Turn over (05)
6 4 Sodium metal has a work function of 2.28 ev. An atom of sodium has an ionisation energy of 5.15 ev. 4 (a) (i) State what is meant by work function. 4 (a) (ii) State what is meant by ionisation energy. 4 (b) Show that the minimum frequency of electromagnetic radiation needed for a photon to ionise an atom of sodium is about 1.2 10 15 Hz. (06)
7 4 (c) Electromagnetic radiation with the frequency calculated in part (b) is incident on the surface of a piece of sodium. Calculate the maximum possible kinetic energy of an electron that is emitted when a photon of this radiation is incident on the surface. Give your answer to an appropriate number of significant figures. maximum kinetic energy =... J 4 (d) Calculate the speed of an electron that has the same de Broglie wavelength as the electromagnetic radiation in part (b). speed =... m s 1 Turn over 12 (07)
8 5 (a) Sketch, on Figure 1, the current voltage (IV) characteristic for a filament lamp for currents up to its working power. Figure 1 I V 5 (b) (i) State what happens to the resistance of the filament lamp as the current increases. [1 mark] 5 (b) (ii) State and explain whether a filament lamp is an ohmic or non-ohmic conductor up to its working power. [1 mark] (08)
9 5 (c) Three identical filament lamps, P, Q and R are connected in the circuit shown in Figure 2. Figure 2 P Q R The filament in lamp Q melts so that it no longer conducts. Explain why lamp P becomes brighter and lamp R becomes dimmer. Question 5 continues on the next page Turn over (09)
10 5 (d) A filament lamp, X, is rated at 60 W 230 V. Another type of lamp, Y, described as energy saving has the same light intensity output but is rated at 11 W 230 V. 5 (d) (i) Calculate the electrical energy converted by each lamp if both are on for 4 hours a day for a period of 30 days. electrical energy converted by X =... J electrical energy converted by Y =... J 5 (d) (ii) Suggest why the two lamps can have different power ratings but have the same light intensity output. 10 (10)
11 6 A potato cell is formed by inserting a copper plate and a zinc plate into a potato. The circuit shown in Figure 3 is used in an investigation to determine the electromotive force and internal resistance of the potato cell. Figure 3 V ma zinc plate copper plate potato 6 (a) State what is meant by electromotive force. Question 6 continues on the next page Turn over (11)
12 6 (b) The plotted points on Figure 4 show the data for current and voltage that were obtained in the investigation. Figure 4 0.8 0.7 0.6 0.5 Voltage / V 0.4 0.3 0.2 0.1 0 0 0.05 0.10 0.15 0.20 0.25 0.30 Current / ma (12)
13 6 (b) (i) Suggest what was done to obtain the data for the plotted points. [1 mark] 6 (b) (ii) The electromotive force (emf) of the potato cell is 0.89 V. Explain why the voltages plotted on Figure 4 are always less than this and why the difference between the emf and the plotted voltage becomes larger with increasing current. 6 (b) (iii) Use Figure 4 to determine the internal resistance of the potato cell. internal resistance =... Ω Question 6 continues on the next page Turn over (13)
14 6 (c) A student decides to use two potato cells in series as a power supply for a light emitting diode (LED). In order for the LED to work as required, it needs a voltage of at least 1.6 V and a current of 20 ma. Explain whether the LED will work as required. 11 (14)
15 7 A cable used in high-voltage power transmission consists of six aluminium wires surrounding a steel wire. A cross-section is shown in Figure 5. Figure 5 aluminium steel The resistance of a length of 1.0 km of the steel wire is 3.3 Ω. The resistance of a length of 1.0 km of one of the aluminium wires is 1.1 Ω. 7 (a) The steel wire has a diameter of 7.4 mm. Calculate the resistivity of steel. State an appropriate unit. [4 marks] resistivity =... unit... Question 7 continues on the next page Turn over (15)
16 7 (b) Explain why only a small percentage of the total current in the cable passes through the steel wire. 7 (c) The potential difference across a length of 1.0 km of the cable is 75 V. Calculate the total power loss for a 1.0 km length of cable. Total power loss... W 10 END OF QUESTIONS Copyright 2015 AQA and its licensors. All rights reserved. (16)